textproduct: Quad Cities

KEY MESSAGES

- Dense fog will be found until mid morning across portions of eastern Iowa and northwest Illinois.

- Cold front to pass through the area on Sunday, bringing the chance for isolated-scattered showers and storms for some. Severe weather is not expected at this time.

- High pressure will bring a period of much needed quiet and dry weather through much of Sunday and Monday.

- A shortwave will drag a cold front through the area Tuesday night into Wednesday, bringing the chance for overnight storms. Some storms may be strong to severe, with severe winds being the main concern.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 131 AM CDT Sun Aug 16 2026

After another bout of rainfall and light/variable winds prior to sunrise Sunday, there will be the chance for some locations to see fog develop. This will largely be favored in eastern Iowa and remain focused along river valleys. Although, given passing clouds and increasing winds out of the northwest near sunrise, this should be a localized threat.

Upper wave passing through the area will slowly drag a cold front through the area today, passing northwest to southeast. This front will be slow to pass through, with it clearing our southeastern half of the area this afternoon. We will see quite the moisture gradient along this front, with dewpoints ahead of it in the mid 70s crashing into the low-mid 60s on the back end tonight. This, along with the shortwave overhead, will allow for showers/storms to develop in the afternoon hours. Overall, we are uncertain on the coverage of the showers/storms. Best chances are currently for areas along/east of the Mississippi River in west-central Illinois. Although, an isolated shower/storm cannot be ruled out along the remainder of the cold front. Heavy rainfall and lightning will be the main concern with any thunderstorm, with the severe risk low. This activity will also be progressive and move out of the area relatively quickly along the front, limiting the flash flood threat. Overall, confidence is low on coverage and short term guidance would favor most locations remaining dry through the day.

This boundary will largely clear the area by early-mid evening Sunday, leaving us with decreasing cloud cover, humidity, and temperatures. From there, surface high pressure will pass over the area on Monday, bringing a beautiful day to start the new work week. There will be plenty of sun, which we have not seen much of lately. Enjoy the beautiful start to the week!

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 131 AM CDT Sun Aug 16 2026

Tuesday and Wednesday...

Upper level northwest flow will remain over the area, which will continue to drive bouts of energy through the region. Long term guidance is in general agreement on a stronger wave passing through Iowa Tuesday night into Wednesday, dragging a cold front through the area. A look at model soundings would indicate that the environment ahead of it will be sufficient for some strong to severe storms. Shear will generally be between 30-40 KTs with modest instability, favoring the chance for some organized convection. A look at the environment and overall pattern would favor the potential for an overnight MCS to potentially impact the area. Main hazards with this would be severe wind gusts, with heavy rain and frequent lightning. The SPC is also highlighting much of the area in a Slight Risk, or level 2/5, for severe weather. There remains some uncertainty on timing and convective coverage, owing to differences amongst guidance. As more short term guidance comes in over the coming days, we will be able to hone in on some of the finer details.

Beyond...

Northwest flow will remain through the remainder of the week, as a ridge builds over the Central CONUS and guides another shortwave through the area on Thursday into Friday. Moisture will remain limited, which should limit precipitation chances. Some guidance brings in overnight PoPs, as a weak LLJ converges into the wave. Although, PoPs are largely <20% area-wide. Thus, much of the area should remain dry going into Friday. The main wave with better forcing will pass through during the day of Friday, bringing low-end PoPs in our north. In the end, much of the area will remain dry through this stretch. The weather is currently geared to be quite nice to end the week, with temperatures in the upper 70s, a mix of clouds/sun, and comfortable humidity.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 550 AM CDT Sun Aug 16 2026

IFR to VLIFR conditions in low clouds and fog will start off the TAF period. Gradual improvement to VFR with SCT-BKN cumulus is expected by afternoon, as winds turn to the WNW and increase to around 10-15 kt with some localized gusts 20+ kt possible. A disturbance shifting eastward from Nebraska will bring chances for showers and storms to the area into this evening. This morning the activity will be south of KBRL, but this afternoon it could develop northward to KBRL and possibly near KMLI ahead of a secondary cold front. Will add PROB30 mention to both sites after 19z through 00z. NNW winds should diminish below 10 kt tonight with enough dry air advection and BL stirring to preclude any fog mention.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Dense Fog Advisory until 9 AM CDT this morning for IAZ040>042- 051>054-063>068. IL...Dense Fog Advisory until 9 AM CDT this morning for ILZ015. MO...None.